Relevance of Chronic Kidney Disease Classification (K/DOQI) in Renal Transplant Patients

Proteinuria 1 year after renal transplantation is associated with impaired graft survival in children

BACKGROUND

Proteinuria is a common manifestation of chronic kidney disease (CKD), and there is a high incidence of CDK and its complications following renal transplantation. However, little data are available on the association between proteinuria and graft/patient survival in the paediatric transplant population. The primary aim of this study was to investigate the associations between posttransplant proteinuria and graft/patient survival in children after renal transplantation.

METHODS

In this retrospective study, we screened all 91 children receiving renal allografts at a single institution between 1997 and 2007. The inclusion criteria were a functioning graft at 1 year posttransplant, data availability and no recurrence of focal-segmental glomerulosclerosis. The final cohort included 75 patients. Proteinuria was considered to be pathologic if the urinary protein/creatinine ratio was >30 mg/mmol. Donor and recipient characteristics, data on proteinuria, estimated glomerular filtration rate (eGFR) and rejection episodes were analysed. The most recent of the biopsies performed during the follow-up after 1 year posttransplant were analysed separately in the proteinuric group and the non-proteinuric group.

RESULTS

Proteinuria at 1-year posttransplant was pathologic in 35 % of patients. The 5-year graft survival rate was significantly lower in the proteinuric group than in the non-proteinuric group (77 vs. 100 %; p < 0.001). Proteinuria at 1 year posttransplant was associated with reduced long-term graft survival independent of other risk factors, including decreased eGFR or episodes of acute corticosensitive and corticoresistant rejection. The most frequent histologic finding in the proteinuric group was chronic rejection. There was no significant difference in the 5-year patient survival rate between the proteinuric group and the non-proteinuric group.

CONCLUSION

This study emphasizes the importance of proteinuria as a prognostic factor of renal allograft survival in children.

Initial vascular access type in patients with a failed renal transplant

BACKGROUND AND OBJECTIVES

Permanent hemodialysis vascular access is crucial for RRT in ESRD patients and patients with failed renal transplants, because central venous catheters are associated with greater risk of infection and mortality than arteriovenous fistulae or arteriovenous grafts. The objective of this study was to determine the types of vascular access used by patients initiating hemodialysis after a failed renal transplant.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the US Renal Data System database on 16,728 patients with a failed renal transplant and 509,643 patients with native kidney failure who initiated dialysis between January 1, 2006, and September 30, 2011 were examined.

RESULTS

At initiation of dialysis, of patients with a failed transplant, 27.7% (n=4636) used an arteriovenous fistula, 6.9% (n=1146) used an arteriovenous graft, and 65.4% (n=10,946) used a central venous catheter. Conversely, 80.8% (n=411,997) of patients with native kidney failure initiated dialysis with a central venous catheter (P<0.001). Among patients with a failed transplant, predictors of central venous catheter use included women (adjusted odds ratio, 1.75; 95% confidence interval, 1.63 to 1.87), lack of referral to a nephrologist (odds ratio, 2.00; 95% confidence interval, 1.72 to 2.33), diabetes (odds ratio, 1.14; 95% confidence interval, 1.06 to 1.22), peripheral vascular disease (odds ratio, 1.31; 95% confidence interval, 1.16 to 1.48), and being institutionalized (odds ratio, 1.53; 95% confidence interval, 1.23 to 1.89). Factors associated with lower odds of central venous catheter use included older age (odds ratio, 0.85 per 10 years; 95% confidence interval, 0.83 to 0.87), public insurance (odds ratio, 0.74; 95% confidence interval, 0.68 to 0.80), and current employment (odds ratio, 0.87; 95% confidence interval, 0.80 to 0.95).

CONCLUSIONS

Central venous catheters are used in nearly two thirds of failed renal transplant patients. These patients are usually followed closely by transplant physicians before developing ESRD after a failed transplant, but the relatively low prevalence of arteriovenous fistulae/arteriovenous grafts in this group at initiation of dialysis needs to be investigated more thoroughly.

KNOW-KT (KoreaN cohort study for outcome in patients with kidney transplantation: a 9-year longitudinal cohort study): study rationale and methodology

BACKGROUND

Asian patients undergoing kidney transplantation (KT) generally have better renal allograft survival and a lower burden of cardiovascular disease than those of other racial groups. The KNOW-KT aims to explore allograft survival rate, cardiovascular events, and metabolic profiles and to elucidate the risk factors in Korean KT patients.

METHODS

KNOW-KT is a multicenter, observational cohort study encompassing 8 transplant centers in the Republic of Korea. KNOW-KT will enroll 1,000 KT recipients between 2012 and 2015 and follow them up to 9 years. At the time of KT and at pre-specified intervals, clinical information, laboratory test results, and functional and imaging studies on cardiovascular disease and metabolic complications will be recorded. Comorbid status will be assessed by the age-adjusted Charlson co-morbidity index. Medication adherence and information on quality of life (QoL) will be monitored periodically. The QoL will be assessed by the Kidney Disease Quality of Life Short Form. Donors will include both living donors and deceased donors whose status will be assessed by the Kidney Donor Risk Index. Primary endpoints include graft loss and patient mortality. Secondary endpoints include renal functional deterioration (a decrease in eGFR to <30 mL/min/1.73 m2), acute rejection, cardiovascular event, albuminuria, new-onset diabetes after transplant, and QoL. Data on other adverse outcomes including episodes of infection, malignancy, recurrence of original renal disease, fracture, and hospitalization will also be collected. A bio-bank has been established for the acquisition of DNA, RNA, and protein from serum and urine samples of recipients at regular intervals. Bio-samples from donors will also be collected at the time of KT. KNOW-KT was registered in an international clinical trial registry (NCT02042963 at http://www.clinicaltrials.gov) on January 20th, 2014.

CONCLUSION

The KNOW-KT, the first large-scale cohort study in Asian KT patients, is expected to represent the Asian KT population and provide information on their natural course, complications, and risk factors for complications.

Diagnostic performance of serum cystatin C and serum creatinine in the prediction of chronic kidney disease in renal transplant recipients

BACKGROUND

Chronic kidney disease (CKD) has adverse impacts on mortality and morbidity of renal transplant recipients. Serum cystatin C (sCysC) is a novel marker in predicting the CKD. We therefore compare sCysC and serum creatinine (sCr) with the aim of improving the detection of CKD in renal transplant recipients.

METHODS

We enrolled 106 renal transplant recipients and estimated glomerular filtration rates (GFR) using the Cockcroft-Gault (GFR(CG)) and the abbreviated Modification of Diet in Renal Disease (GFR(aMDRD)) formulae. We defined CKD as the presence of structural or functional kidney damage, irrespective of the diagnosis. Comparisons of sCysC and sCr in detecting CKD were analyzed.

RESULTS

sCysC correlates with sCr significantly (r = 0.87; P < .001). The receiver operating characteristic curve demonstrates that sCysC has a better specificity and area under the curve, but less sensitivity than sCr in predicting CKD in renal transplant recipients if GFR is estimated by GFR(CG). Additionally, if GFR was estimated by GFR(aMDRD), the role of sCysC or sCr in prediction of CKD was comparable.

CONCLUSION

sCysC may be better than sCr to detect CKD in renal transplant recipients using the GFR(CG).

Prevalence and complications of chronic kidney disease in paediatric renal transplantation: a K/DOQI perspective

Background. Although renal transplant recipients (RTR) have been included as patients with chronic kidney disease (CKD) by the Kidney Disease Outcome Quality Initiative (K/DOQI), there are very few studies looking at CKD complications among paediatric RTR. Methods. CKD parameters of paediatric RTR with at least 1 year post-transplant follow-up were retrospectively reviewed as per K/DOQI criteria. Results. The study population included 129 RTR aged 2.7-20 (median 13.9) years, of which 67% were male and 87% Caucasian with follow-up between 1 and 14.8 (median 3.8) years. Sixty-six per cent of RTR were in either CKD Stage 3 (70) or 4 (15). A high incidence of CKD complications was identified (albuminuria 60%, anaemia 50%, acidosis 30%, hyperparathyroidism 20%, hypoalbuminaemia 16%, hyperphosphataemia 12% and hypocalcaemia 3%). Hypertension (defined as systolic blood pressure greater than 95th percentile for age and height or on any anti-hypertensive medication) was found in 53% (n = 68) of the study population, out of which 7% (n = 5) was having uncontrolled hypertension with systolic blood pressure greater than 95th percentile despite being on anti-hypertensive medication. There was an increase in complications (P = 0.0001) as well as use of CKD medications (erythropoietin-stimulating agent, sodium bicarbonate, 1-alfacalcidol and phosphate binders) across the CKD stages in RTR (P = 0.001). Conclusion. The study confirmed a high prevalence of CKD with its related complications along with increase in frequency of complications across the stages of CKD among paediatric RTR. Further multi-centre prospective studies are required to substantiate our findings and to explore whether early identification and intervention can improve renal allograft outcome.

[Can the renal transplant patient be really considered as a patient with chronic renal insufficiency?]

To assess if the renal transplant patient can really be considered as a patient with chronic renal insufficiency, disease progression and outcomes were compared in both groups. At the same stage of chronic kidney disease (CKD), the deterioration of renal function was slower and graft survival was longer in renal transplant patients. Despite slower rates of kidney function decline, overall patient survival was similar between the two groups. Interestingly, stage 3 adjusted mortality rates were greater in kidney transplant recipients, most likely because of the disease burden (history of end-stage renal disease in renal transplant recipients) and immunosuppression. The three major causes of mortality in transplant patients (cardiovascular, infectious and malignant) may present with specific characteristics in transplant patients. Renal transplantation is thus a specific form of CKD, controlled by 3 factors, a single kidney, immunosuppression and the burden of the disease. The general application of the KDOQI and KDIGO guidelines to kidney transplant recipients requires therefore further evaluation.

Complications of chronic kidney disease in children post-renal transplantation - a single center experience

Similar to adults, CKD may persist after pediatric RTx. Clinical and laboratory parameters were analyzed retrospectively in 23 RTx recipients (13 males, age 11.9 +/- 5.2 yr), initially treated with prednisone, calcineurin inhibitor (TAC = 18, cyclosporine neoral = 5), and MMF at four months post-RTx (T1) and at 3.4 +/- 2.8 yr post-RTx (T2). Mean (+/-s.d.) cystatin C GFR (mL/min/1.73 m(2)) was 72 +/- 19 at T1 and 70 +/- 22 at T2 (NS). At T2, CKD stage I was present in five patients (22%), stage II in eight patients (35%), and stage III in 10 patients (43%). At T2, calcineurin inhibitors were utilized in 19, MMF in 13, and SIR in 13 patients. The prevalence of hypertension was 69% at T1 and 87% at T2 (p = NS). Anemia was diagnosed in 61% at T1 and 69% at T2 with average therapeutic MMF (2.78 +/- 1.3 mg/mL) and SIR (7.62 +/- 2.3 mg/mL) trough levels. Hypercholesterolemia was detected in 44.0% at T1 and 47% at T2. Bone disease was diagnosed in 26.0% at T1 and 21.7% at T2. Mean height Z-scores were -1.0 +/- 1.2 (T1) and -1.0 +/- 1.59 (T2, NS), with 21% at T1 and 30% at T2 below two SDS. We observed suboptimal growth, hypertension, hypercholesterolemia, bone disease, and anemia in a significant proportion of transplanted children.